Current feeder to a moving current carrying surface

ABSTRACT

A CURRENT FEEDER TO THE CURRENT-CARRYING SURFACE OF AN ELECTRIC FURNACE HAS A BRUSH WITH A GROOVE TO RECEIVE THE BLADE OF A KNIFE. THE SHAPE OF THE GROOVE CORRESPONDS TO THE V-SHAPE OF SAID BLADE ALLOWING THE BRUSH TO FREELYL SHIFT WITH RESPECT TO THE KNIFE REMAINING UNIFORMLY PRESSED AGAINST THE MOVING SURFACE.

United States Patent 3,714,368 CURRENT FEEDER TO A MOVING CURRENT- CARRYING SURFACE Konstantin Trofimovich Nautny, Viktor Iosifovich Lakomsky, and Anatoly Ivanovich Chvertko, Kiev, Semen Yakovlevich Shekhter and Alexandr Mikhailovich Reznitsky, Kommunarsk Voroshilovgratlskoi Oblasti, and Viktor Romanovich Pilipchuk, Kiev, U.S.S.R., assignors to Institut Elektrosvarki Imeni E. 0. Patona Akademii Nauk Ukrainskoi SSR, Kiev, U.S.S.R.

Filed Feb. 17, 1972, Ser. No. 227,188 Int. Cl. H05b 7/10 US. C]. 13-16 2 Claims ABSTRACT OF THE DISCLOSURE A current feeder to the current-carrying surface of an electric furnace has a brush with a groove to receive the blade of a knife. The shape of the groove corresponds to the V-shape of said blade allowing the brush to freely shift with respect to the knife remaining uniformly pressed against the moving surface.

The invention relates to electrometallurgy and, more particularly, to devices for feeding the electric current to moving surfaces of current-carrying assemblies in electric furnaces.

The prior art devices used to supply large currents to consumable blanks and to ingots to be smelted.

These devices are usually designed either as flexible copper cables (stubs) or as sliding contacts (brushes). Current feeders made as flexible cables (short-distance circuits) are required to be highly flexible. At the same time, from considerations of the allowable current density they should have a suflicient cross section. To make the current feeder fiexible, the designer tends to increase its length, thus raising its effective resistance, which is utterly undesirable. Besides, the major requirement that a shortdistance circuit being designed should meet is a loW inductive reactance which, as rule, is a number of times as high as the effective resistance. There are instances when, in order to reduce the length of a current feeding circuit and to lower the inductive reactance and effective resistance, sliding contacts (brushes) are used in electric furnaces, e.g. in furnaces for slag remelting. The brushes of this design are pressed against the moving surface with the aid of hydraulic devices which, to a certain degree, ensure the tightness of contact between the brush and the surface. However, the design of such current feeders is extremely complicated, which results in reduction of their reliability in operation. Moreover, in case of a high temperature and low vacuum, e.g. for feeding current to a consumable blank in an arc-plasma furnace, these devices can not be used at all, since even the slightest oil leakage from the current feeder located inside the furnace chamber would produce oil vapour and hence considerably impairs the quality of the ingot metal.

An object of the present invention is to avoid these difficulties.

Another object of the present invention is to provide a current feeder Whose design will permit it to supply currents to current-carrying units of electric furnaces and which will operate reliably irrespective of temperature conditions.

With these and other objects in view, there is provided a current feeder to a moving current-carrying surface, comprising a conducting brush pressed against said surface with the blade of an elongated knife fixed at the end of a spring-loaded lever, While the brush, according to the invention, has a groove made in the area where the knife is pressed against it, the groove allowing the ice.

brush to shift freely with respect to the knife remaining uniformly pressed against the moving surface.

The said groove is V-shaped and its length and expansion angle exceed the length and the angle of taper of the knife blade.

This design of the device will make it widely applicable in special electrometallurgy as a current feeder to moving surfaces allowing to considerably reduce the length of the current conducting circuit (from the power supply to the furnace) and, hence, to bring down its effective resistance and, which is much more important, its inducti-ve reactance.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings which:

FIG. 1 presents a partially cut away general view of the device with two brushes, according to the invention;

FIG. 2 is the section along H--II of FIG. 1.

The current feeder to a moving surface comprises a brush 1 (FIGS. 1 and 2) and a pressing device.

The brush 1 is made as a rectangular shoe and serves to feed an electric current to or pick it up from, a moving surface.

The bottom section of the brush 1 that runs along its greater side is curved at a constant radius equal to that of the moving surface cylinder. In the centre of its upper section the brush has a lateral V-shaped groove 2. Made in the both sides of the brush body are two threaded holes with bolts screwed into them to secure the caps of current feeding flexible cables.

The pressing device is provided with a knife 4 serving to press the brush 1 to a moving surface 5 '(stem). At one end of the knife there is a blade inserted into the V-shaped groove 2 of the brush 1, while at the other, there is a cylindrical shank with a threaded end. The shank of the knife 4 is inserted into a hole at the butt of a lever 6 and is rigidly secured there in the required position with the aid of a nut 7. The angle of taper of the blade of the knife 4 is a little smaller than the expansion angle of the V-shaped groove 2 on the brush 1, while the length of the blade is shorter than that of the groove 2.

The lever 6 is hinged by means of a pin 8 on a prop 9 of a stationary tube 10. The lever 6 with the knife 4 fixed at its end serves to press the brush 1 against the moving surface with the help of a spring 11. Made in the middle section of the lever 6 is a cylindrical hole with a platform (not shown in the drawing). Passing through the hole is a prop 12 screwed into the tube 10.

The spring 11 is put on the prop 12 to rest on both sides against bushes 13 which prevent it from rubbing against the prop 12 and the walls of the lever 6.

The device operates as follows.

The lever 6 is pulled back, the brush 1 is mounted onto the knife 4 so that its V-shaped groove receives the blade of the knife and the lever 6 is released. Then, the contact side of the brush 1 is brought to rest against the moving surface 5 of the stern along the generating lines. To do this, it is necessary to unscrew the nut 7 and by bringing down the end of the lever 6 press the brush 1 against the stem surface 5 with the knife 4. Here, the knife 4 and the brush 1 will get fixed in the required position making the latter abut properly against the moving surface 5. Then, the nut 7 is tightened.

Since the angle of taper of the blade of the knife 4 is a little smaller than the expansion angle of the V-shaped groove 2 of the brush 1 While the groove 2 is longer than the blade, the brush can, on the one hand, rotate freely with respect to the blade of the knife 4 following the moving surface 5 of the stem, and on the other, it can shift along the blade (float) in the plane normal to the direction of the displacement of the contact surface 5 of the stem. Thus, it becomes possible to ensure the uniform pressing of the blade of the knife 4 of the brush 1 against the moving surface 5 compensating for manufacture inaccuracies.

When the device is used to feed an electric current to flat surfaces the knife 4 prevents the brush 1 from rotating relative to the knife.

The force required to press the brush 1 against the moving surface 5 of the stem is produced by means Of tightening the nut 14 on the prop 12.

This design of the current feeder results in the maximum abutment of contacting surfaces and helps to avoid substantial contact resistances for the current.

What is claimed is:

1. A current feeder to a moving current-carrying surface comprising: a spring-loaded lever, an elongated knife secured at the end of said spring-loaded lever, a conducting brush pressed against said moving surface by the blade of said knife and provided with a groove at the area Where the knife is pressed against the brush to receive the blade of the knife, the shape of the groove being similar to that of said blade and allowing the brush to shift freely with respect to said knife remaining uniformly v pressed against the moving surface.

2. A current feeder as of claim 1, in which said groove is V-shaped while its length and angle of expansion exceed the length and the angle of taper of the blade of said knife.

References Cited UNITED STATES PATENTS ROY N. ENVALL, JR., Primary Examiner US. Cl. X.R.

l7486; 2l9l29; 3399 R; 310246 

